1. Field of the Invention
This disclosure pertains in general to the field of medical devices and methods. More particularly, the disclosure relates to a medical device for improving the function of a heart valve, and in particular to replacement or repair of a native heart valve.
2. Description of the Prior Art
In FIG. 1, a portion of the heart 12 is illustrated. The portion comprises the mitral valve 18, and the left ventricle 14. The mitral valve is at its boundary circumferenced by an annulus 20. The valve has two cusps or leaflets 22, 24. Each of these cusps or leaflets 22, 24 are connected to a respective papillary muscle 27, 29 via their respective connecting chordae 26, 28. In normal healthy individuals, the free edges of the opposing leaflets 22, 24 will close the valve. However, for some individuals the closure is not complete, which results in regurgitation, also called valvular insufficiency, i.e. a back flow of blood to the left atrium and potentially increasing blood pressure in pulmonary circulation making the heart less effective and with potentially severe consequences for the patient. FIG. 2 illustrates a mitral valve 18, in which the leaflets 22, 24 do not close properly. This commonly occurs when the annulus 20 becomes dilated. One surgical procedure to correct this is to remove a portion of the leaflet 24 and stitch the cut edges together with one another. The procedure will pull back the annulus 20 to a more normal position. However the strength of the leaflet 24 is altered. Similar problems with a less effective heart function may occur if one or both leaflets 22, 24 are perforated to such an extent that blood is flowing towards the left atrium, although the leaflets close properly.
In some conditions of degenerated heart function, the leaflets 22, 24 do not present a solid surface, as in a degenerative valve disease. The leaflet could also be perforated, with one or several holes, where the blood can flow backwards into the atrium.
Another possibility is that the leaflet is ruptured, most commonly at an edge of a leaflet, resulting in an incomplete coaptation. In some conditions of degenerated heart function, the leaflets do not present a solid surface, e.g. degenerative valve disease. The leaflet could be perforated, with one or several holes, where the blood can flow backwards into the atrium. Another possibility is that the leaflet is ruptured, most commonly at an edge of a leaflet, resulting in an incomplete coaptation.
Similar problems may arise in other native heart valves, such as in an aortic valve, in a pulmonic valve or in a tricuspid valve.
Some or all of these deficiencies may be remedied by the insertion of a prosthetic heart valve. However, it may be difficult to fit the prosthetic heart valve tightly to the native heart valve and thus, there may be a back-flow or leakage between the annulus or other surrounding valve tissue and the prosthetic heart valve.
Hence, an arrangement and/or a method for replacement or repair of a native heart valve, in which there is no paravalvular leakage or regurgitation between a prosthetic heart valve and the surrounding valve tissue, would be advantageous.
Furthermore, for fastening of such a prosthetic heart valve, replacement flaps can be used. Such replacement flaps can be anchored at dysfunctional flaps of the native heart valve and thereby give radial supporting force to the prosthetic heart valve, which is therefore also anchored. There is some prior art in this field, e.g. EP 1 994 913 A2; EP 1 469 797 B1; EP 1 259 195 B1; WO 2007/051620 A1; WO 2007/048529 A1; EP 1 980 220 A1; WO 01/64137 A1; EP 1 255 510 B3; U.S. Pat. No. 5,411,552 A and WO2008/058940 A1. From WO2008/058940 A1, a device for improving the function of a heart valve is known, which comprises a first loop-shaped support, which is configured to abut a first side of a heart valve, and a first flange unit being connected to the first loop-shaped support. The flange unit is configured to be arranged against the annulus when the first loop-shaped support is abutting the heart valve.
However, for a device, such as the one described in WO2008/058940 A1, it may be advantageous to provide for a prosthetic valve, which is positionable tightly towards a loop-shaped support.
Moreover, for a device, such as the one described in WO2008/058940 A1, it may be advantageous to improve support of the positioning of a prosthetic heart valve inside the loop-shaped support.
In addition, for a device, such as the one described in WO2008/058940 A1, it may be advantageous to seal the area between the prosthetic heart valve and a loop-shaped support.